The present invention relates to an input device of electronic appliances such as typewriter, word processor and personal computer, and more particularly to an input device having plural stroke keys and plural touch keys mounted on a common FPC board.
Conventionally, in the input devices of electronic appliances such as typewriter, personal computer and word processor, generally stroke keys which possess a tactile feed back effect, excel in controllability and rarely malfunction are used.
For example, the Japanese Patent Publication (non-examined) No. 58-181213 discloses stroke keys which are designed so that the key tops of the stroke keys may be detached from the keyboard main body and exchanged with other key tops differing in size.
In this kind of input device, in order to lower the manufacturing cost, stroke keys are disposed, corresponding to each contact point of the electric contact matrix of a flexible printed circuit board (FPC board) generally.
Then by the key scan control executed by the control unit of the input device, the operated key is discriminated and the ON action and OFF action are judged.
On the other hand, in the keyboard of an input device of pocket calculator and card type computer, small and inexpensive touch keys are used.
For example, the Japanese Patent Publication (non-examined) No. 58-10325 discloses an input device composed of multiple character keys disposed in a character display region and multiple function keys disposed in a function display region, which comprises touch keys designed to obtain a large operation reaction by the reinforcing plate assembled in a flexible switch cover of the function keys in the function display region because a sufficient operating reaction cannot be obtained in function keys which are larger than character keys.
In the case of an input device of an electronic appliance, in order to discriminate the operated key and judge the ON action and OFF action, key scan control is executed in a control unit, and to prevent complication of the key scan control, in the conventional input device, either stroke keys or touch keys are used.
Recently, as the functions are rapidly sophisticated in the electronic typewriter, word processor and other electronic appliances, the number of keys in the input device tends to increase, but when the stroke keys are increased, the keyboard becomes larger in size, the manufacturing cost becomes very high.
It is undesirable to use the small and inexpensive touch keys to entirely replace the stroke keys, since for the tough keys, the pressing stroke is very small and sufficient tactile feedback cannot be obtained, and the controllability is poor. Besides, when used for a long time, fatigue of fingertips is significant, and malfunction by chattering is likely to occur because of operation by soft fingertips so that a longer time may be required to judge the ON action and OFF action in key scan control, which results in reduction of the key operation speed.
It is hence a primary object of this invention to present an input device comprising stroke keys and touch keys, possessing the advantages of both stroke keys and touch keys. It is a secondary object of this invention to present an input device capable of performing key scan control without sacrificing the characteristics of both stroke keys and touch keys. And it is a tertiary object of this invention to present an input device comprising stroke keys and touch key which is not lowered in the controllability.